The CAM result is either positive (delirium present) or negative (delirium not detected). A positive CAM requires Feature 1 (acute onset and fluctuating course) AND Feature 2 (inattention) to both be present, PLUS either Feature 3 (disorganized thinking) OR Feature 4 (altered level of consciousness). If this diagnostic algorithm is not fully met, the CAM is negative.

A positive CAM result indicates the patient is likely experiencing delirium, which is a medical emergency that requires immediate investigation for an underlying cause. Common precipitants include infection (urinary tract infection, pneumonia), medication effects (opioids, benzodiazepines, anticholinergics), metabolic derangements (electrolyte abnormalities, hypoglycemia, uremia), urinary retention, constipation, pain, and acute cardiac or neurologic events. A thorough history, physical examination, and targeted laboratory workup should be initiated promptly.

A negative CAM result does not completely exclude delirium, particularly hypoactive delirium, which presents with lethargy and decreased activity rather than the classic agitated, confused picture. Hypoactive delirium accounts for up to 50% of delirium cases and is frequently missed because patients appear quiet and compliant. If clinical suspicion remains despite a negative CAM, reassessment at a later time or use of a more sensitive tool (such as the CAM-ICU or 3D-CAM) should be considered.

Use the CAM as a bedside screening tool for delirium in any hospitalized patient, particularly older adults (65 years and older), who demonstrates acute changes in mental status, behavior, or cognition. Delirium affects up to 50% of hospitalized elderly patients and up to 80% of mechanically ventilated ICU patients, making routine screening essential. The CAM is recommended for daily screening in high-risk populations including postoperative patients, ICU patients, patients with hip fractures, patients with dementia, and those with multiple comorbidities.

The CAM is also useful in the emergency department for rapid delirium identification in confused older patients. It helps differentiate delirium from dementia, depression, and psychosis, each of which requires different management. Screening should be performed upon admission, after surgery, after any acute change in clinical status, and daily in high-risk patients. The assessment takes approximately 5 minutes when performed by a trained clinician.

The CAM's reported sensitivity of 94% and specificity of 89% were achieved when administered by trained clinicians following a structured cognitive assessment protocol. When used without formal training or without preceding cognitive testing (such as the Mini-Mental State Examination or digit span testing), sensitivity drops significantly — some studies report sensitivity as low as 46% among untrained nursing staff. Proper training in administering and scoring the CAM is essential for reliable results.

The standard CAM is designed for verbal, non-intubated patients who can participate in a brief cognitive assessment. It is not appropriate for mechanically ventilated patients, for whom the CAM-ICU (a modified version) should be used. It may also be difficult to apply in patients with severe aphasia, profound hearing loss, or pre-existing severe dementia, as these conditions can confound the assessment of inattention and disorganized thinking.

The CAM provides a dichotomous result (positive or negative) and does not quantify delirium severity. For severity assessment, the CAM-S (Confusion Assessment Method - Severity) or the Delirium Rating Scale should be used. The CAM also represents a single point-in-time assessment, and delirium is by definition fluctuating — a patient may screen negative at one time and positive hours later. Serial assessments throughout the day increase detection sensitivity.